Recently, wind turbines have received increased attention as environmentally safe and relatively inexpensive alternative energy sources. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Generally, a wind turbine includes a rotor having multiple blades. The rotor is mounted to a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility grade wind turbines (i.e., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 30 or more meters in length). In addition, the wind turbines are typically mounted on towers that are at least 60 meters in height. Blades on these rotors transform wind energy into a rotational torque or force that drives one or more generators that may be rotationally coupled to the rotor through a gearbox. The gearbox steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy, which is fed into a utility grid. In order to provide the efficient conversion of mechanical energy to electrical energy, the wind turbine utilizes a variety of wind turbine components that are too heavy and/or awkward to manually carry, such as shafts, gearing components, pitch drives, generator components and other components within the wind turbine.
Components in the wind turbine typically have to be installed, serviced or replaced using mobile land-based cranes and/or manually carrying components to remove and/or replace components. Wind turbine components may be huge or awkward to handle, precluding manual transportation of the components. Further, wind turbines may be installed on uneven terrain and/or on very high towers (e.g., towers that are at least 60 meters in height) that are inaccessible to mobile land-based cranes. In addition, operation of mobile land-based cranes is expensive.
Therefore, what is needed is an inexpensive method and apparatus for installing, servicing or replacing components in wind turbines that is portable, lightweight and/or is capable of operation at the operating heights of wind turbines and in the various terrains in which wind turbines may be installed.